Apparatus improvements in temperature-conditioning parts

ABSTRACT

Apparatus for temperature-conditioning workpieces comprises a series of bar assemblies for supporting a number of elongated molded parts in side-by-side relationship, heat transfer assemblies including horizontally spaced panels extending along a chamber, means for conveying the parts supported in the bar assemblies through the chamber between the panels and rotating means operatively interconnected with the conveying means and bar assemblies for turning the parts. Infeed means sequentially release loaded bar assemblies at regular intervals to the chamber while metering means preferably driven through downstream equipment continuously release bar assemblies to the discharge end of the chamber. Reciprocable gate means allow temperatureconditioned parts to drop out of the bar assemblies to collection equipment. Process improvements include a.) varying parts conditioning time by varying the number of bar assemblies in the fixed length chamber; b.) maintaining a temperature gradient between circumferentially uneven thick and thin sections of a preform wall to be reshaped into a molecularly oriented article in order to even out wall thickness reductions occurring during stretching in the article forming step.

United States Patent [1 1 Berggren et al.

[ 1 July 15, 1975 APPARATUS IMPROVEMENTS IN TEMPERATURE-CONDITIONINGPARTS [73] Assignee: Monsanto Company, St. Louis, Mo.

[22] Filed: Nov. 21, 1973 [21] Appl. No.: 418,075

[52] US. Cl. 432/124; 432/11; 432/126 [5 1] Int. Cl F27b 9/14 [58] Fieldof Search 432/11, 124, 126

[56] References Cited UNITED STATES PATENTS 3.320,397 5/1967 Alexanderet a1. 432/11 3.822980 7/1974 Graeper 432/124 Primary- Examiner-John J.Camby Attorney, Agent, or FirmMichael J. Murphy [57] ABSTRACT Apparatusfor temperature-conditioning workpieces comprises a series of barassemblies for supporting a number of elongated molded parts inside-by-side relationship, heat transfer assemblies includinghorizontally spaced panels extending along a chamber, means forconveying the parts supported in the bar assemblies through the chamberbetween the panels and rotating means operatively interconnected withthe conveying means and bar assemblies for turning the parts lnfeedmeans sequentially release loaded bar assemblies at regular intervals tothe chamber while metering means preferably driven through downstreamequipment continuously release bar assemblies to the discharge end ofthe chamber. Reciprocable gate means allow temperature-conditioned partsto drop out of the bar assemblies to collection equipment Processimprovements include a.) varying parts conditioning time by varying thenumber of bar assemblies in the fixed length chamber; b.) maintaining atemperature gradient between circumferentially uneven thick and thinsections ofa preform wall to be reshaped into a molecularly orientedarticle in order to even out wall thickness reductions occurring duringstretching in the article forming step.

29 Claims, 11 Drawing Figures SHEET 4 El III .5- 52 APPARATUSIMPROVEMENTS IN TEMPERATURE-CONDITIONING PARTS BACKGROUND OF THEINVENTION This invention is directed toward method and apparatusimprovements for temperature-conditioning workpieces such as elongatedthermoplastic parts which are to be subsequently further shaped intomolecularly oriented hollow articles such as containers.

In U.S. Pat. No. 3,754,851, a system is disclosed for blowing articlesfrom molded preforms which are brought to orientation temperature in anintermediate conditioning step. In this approach heat is removed fromthe preform during conditioning and such has become known in the art asa cool-down" process. It is likewise known to add heat to preforms tobring them up to orientation temperature prior to finish forming as istypically disclosed in U.S. Pat. No. 3,715,109 and other related priorart, and such has become known in the art as a reheat" process. In highspeed, high capacity forming lines utilizing either of these approaches,it is clearly desirable to optimize the temperatureconditioning part ofsuch techniques in order to keep fabricating costs related to this stepat an absolute minimum. Thus, it is desirable to process a large numberof parts at the same time, to minimize handling and reorienting movementof the distortable parts during conditioning, to provide flexibility ofconditioning to accommodate different input temperatures and to exposeeach part as uniformly and completely as possible to the heat sink tominimize exposure time and complexity of apparatus.

Though the above-mentioned prior art has generally been successful inimplementing cool-down and reheat processing, it is deficient in one ormore aspects of the temperature-conditioning phase, especially when suchconditioning is considered in the environment ofa high speed,continuous, large capacity forming line.

Also, with respect to cool-down processes such as disclosed in U.S. Pat.No. 3,754,851, it has been noted that thickness variations in the wallof the thermoplastic preform traceable back to a non-homogeneous meltwherein portions during extrusion are more fluid than others, arecarried over into the final molding step and appear as similarvariations in the finished article. Such variations adversely affectperformance especially when the article is a container such as a bottleintended for holding pressure. This differential thickness occurring inthe circumferential direction is most pronounced when the preform isshaped by blowing from an extruded parison (though it occurs to a lesserextent in injection molding), and should be accommodated, especially ifblown preforms are to represent a viable path to oriented containers forpressurized applications.

SUMMARY OF THE INVENTION Now, there has been developed improvements intemperature conditioning especially adapted for use with parts intendedto be subsequently blown into molecularly oriented articles, which avoidthe aforementioned prior art shortcomings.

Accordingly, it is a basic object of this invention to provideimprovements in temperature-conditioning workpieces.

Another object of this invention is to provide improvements tofacilitate efficient handling of a large number of elongated moldedparts during temperature conditioning.

A further object of this invention is to provide improvements in blowmolding molecularly oriented containers such as bottles intended forpressurized applications.

An additional object of this invention is to provide improvements intemperature-conditioning preforms which are to be shaped in downstreammolding equipment into molecularly oriented articles.

A specific object of this invention is to provide improvements in thetemperature-conditioning stage of a cool-down process for formingmolecularly oriented containers which result in improved uniformity ofwall thickness in such containers.

A specific object of this invention is to provide for varying theresidence time of parts in a temperatureconditioning zone independent ofthe rate of discharge of the parts from the zone and of the temperatureof the heat transfer medium in such zone.

A further object of this invention is to provide means for carrying outthe above-mentioned objects,

Another object of this invention is to provide simplified means forrotating elongated workpieces about their axes during conditioning.

Other objects of this invention will in part be obvious and will in partappear hereinafter.

These and other objects are accomplished in a process for conditioningmolded parts by passing them through a chamber containing heat transferassemblies while the parts are in fixed position with respect to eachother in the direction of movement through the chamber and thencontinuously discharging the parts from said chamber at a constant rateafter conditioning, by providing the improvement which compriseschanging molded part residence time in the chamber by varying the lengthof the path of exposure to the heat transfer assemblies while keepingthe temperature of the assemblies, the position of the parts withrespect to each other and the discharge rate, substantially constant.

Specific process aspects comprise loading a plurality of elongatedmolded parts in side-by-side relationship into consecutively presentedparts-supporting bar assemblies at a charging station, passing the partswhile so supported in one direction along a series of generally parallelpaths between adjacent heat transfer assemblies, rotating the partsabout their vertical axes during movement along such paths whiletransferring heat between the parts and heat transfer assemblies,discharging the parts by gravity from the bar assemblies aftertraversing such paths and then recycling the empty bar assemblies to thecharging station to receive additional parts.

Also, when a molecularly oriented container of thermoplastic material isbeing formed by molding a preform from such material which has a bodywith varying circumferential wall thickness portions at differentrelative temperatures in excess of those at which substantial molecularorientation can be developed, passing the preform through a conditioningzone to'bring the material temperature in such portions to within therange at which substantial orientation can be developed and thenstretching and blowing the temperatureconditioned preform to form thecontainer, there is provided the improvement which comprises avoidingdevelopment of a uniform temperature in the body during passage throughsuch conditioning zone in order to maintain a temperature differentialbetween thick and thin sections of the body during stretching andblowing.

The apparatus comprises horizontally space, longitudinally extendingheat transfer assemblies in a chamber defining the aforementioned paths,a plurality of bar assemblies for simultaneously supporting a pluralityof such parts in vertical position, means for advancing the barassemblies through the chamber along the paths and rotating meansoperatively interconnected with the advancing means and the barassemblies for turning the parts about their axes. A bar assemblycomprises a housing having a series of horizontally spaced openings inwhich are situated part-supporting and rotating mechanisms. The rotatingmeans preferably includes a shaft extending through each bar assemblyhaving spaced worm sections in meshing engagement with theparts-supporting and rotating mechanisms and sprockets at opposite endsrotatably engaging the advancing means.

Metering means are provided for sequentially releasing bar assemblies tothe discharge end of the chamber, as are infeed means for cyclicallyreleasing bar assemblies at regular intervals to the chamber. When thepreforms are being reshaped into molecularly oriented containers indownstream molding equipment, the latter preferably drives the meteringwheels directly in synchronism with movable hopper means beneath thedischarge end of the chamber for accepting the parts as they arereleased from the bar assemblies.

BRIEF DESCRIPTION OF THE DRAWINGS In describing the overall invention,reference will be made to the accompanying drawings wherein:

FIG. I is a vertical, partially schematic, sectional view oftemperature-conditioning apparatus embodying the invention;

FIG. 2 is a vertical, sectional view of the discharge end of theapparatus taken along 22 in FIG. 1;

FIG. 3 is a partial, sectional, plan view of the partsholding androtating components positioned at the discharge end of the apparatus,taken along 3-3 of FIG.

FIG. 2 is partially sectioned, elevational view taken along 44 of FIG.3;

FIG. 5 is a partial, sectional view taken along S5 of FIG. 3;

FIG. 6 is an enlarged vertical sectional view of a track portion of theapparatus of FIG. 1;

FIG. 7 is an enlarged, partially sectioned, schematic view of componentsat the discharge end of the apparatus of FIG. 1, taken at 90 to that ofFIG. 2;

FIG. 8 is a plan view of components shown in FIG.

FIG. 9 is a view similar to FIG. 2 of the feed end of the apparatustaken along 99 of FIG. 1;

FIG. 10 is a plan view taken generally in the direction l0-10 of FIG. 2;and

FIG. 11 is a vertical, schematic view of a molding station downstream ofthe apparatus of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to thedrawings, there is illustrated in FIG. I, apparatus 10 fortemperature-conditioning elongated molded parts. Apparatus 10 compriseswall sections formed of a suitable material such as sheet metal whichinclude opposing vertical side panels and 12b (FIG. 2) and top panel 14(FIG. I) which may be divided into pieces provided with handles 16forming removable covers such as 18. Horizontal support members 20 spanthe space between panels 120 and 12b and support heat transfer units,such as 21 (FIG. 7), secured thereto and positioned in end to endrelationship so as to form a horizontally extending heat transfer zoneor chamber generally indicated as 22. Three such units are typicallyillustrated in FIG. 1. Each unit 21 has a base portion whichcollectively form floor member 24 dividing chamber 22 into an uppercourse 26 (FIG. 2) and a lower course 28, such lower course 28 beingdownwardly open to the surroundings along its length. Insulation such as33 in FIG. 4, may be provided as necessary to prevent loss of heat tothe surroundings. Chamber 22 has a feed end generally indicated at 30 inFIG. 1 at which is located a charging or loading station, and anopposite discharge end similarly indicated at 32.

Each heat transfer unit 21 comprises a heat transfer assembly whichincludes upright panels 38 spaced from each other in the horizontaldirection and extending along the length of chamber 22. Each panel 38(FIG. 2) is secured to its portion of floor member 24 and contains flowchannels generally indicated as 40 in FIG. 1 in serpentine form havingmeans including tube portions 42 and 44 connected via suitableconventional valving into a reservoir for circulating a heat transfermedium under pressure through channels 40, for the purpose ofcontrolling the air temperature between adjacent panels. A narrow,generally parallel path 39 (FIG. 2) is therefore formed by adjacentpanels 38 for the parts being temperature conditioned and which ispreferably only slightly greater in width than that of the portion ofthe parts being conditioned. In the illustrated embodiment, ten suchpaths or channels 39 are shown.

A plurality of bar assemblies 48 (FIG. 3) support workpieces such aselongated molded parts 50 (FIG. 1) in suspended vertical positionbetween adjacent panels 38. Each bar assembly 48 when in aparts-conditioning position within chamber 22 is situated immediatelyabove panels 38 (FIG. 1) and arranged for movement from feed end 30 todischarge end 32 and back again in an endless path in a manner to bedescribed. Bar assembly 48 includes annular, part-supporting androtating mechanisms 51 (FIGS. 3 and 4), situated in a series ofhorizontally spaced, linearly arranged openings 52 formed in avertically thin, horizontally long, rectangular housing 54, each suchmechanism being vertically aligned above a path 39 when inpart-supporting position in apparatus 10. Though assemblies 48 in theillustrated embodiment are above panels 38 when in the heat transferzone of the apparatus because of the particular configuration of parts50 being treated, it is possible to position them beneath heating unitswith parts being treated seated therein in an upright position. Eachmechanism 51 comprises part support insert or socket 56 having a collar58 at its lower end for cooperating with step portion 60 adjacent theopen end 62 of elongated molded part 50 in the manner particularly shownin FIG. 4. Insert 56 is secured by suitable means such as a pin in avertical slot, not shown, to annular pinion 64 seated in opening 52 bymeans of frictional engagement with the wall thereof. Each assembly 48may include a brake mechanism 66 operatively associated with shaft 74which in the illustrated embodiment comprises shoe member 68 in forcedsurface contact by means of compression spring 70 with a collar 72 fixedon shaft 74, the latter to be further described hereafter. The forceurging member 68 against collar 72 may be set by means of adjustingscrew 73 threadably engaged with the surface of bore 71 containingspring 70. Though any material may be used, housing 54, pinion 64 andpart-support insert 56 are preferably formed of a strong, low heatconductive material such as fiber-reinforced phenolic plastic.

Means (FIGS. 1 and 3) for advancing each bar assembly 48 through chamber22 comprises an endless chain 80 (FIG. 1) on each side of chamber 22extending lengthwise thereof and a pair of sprockets 82 and 83 (FIGS. 1and 4) for each such chain at the feed end 30 and discharge end 32respectively of chamber 22. Chains 80 are double stranded at 85 and 87and sprockets 82 and 83 are preferably likewise of double constructionwith the teeth on the outer side (FIG. 9) removed to accommodate drivensprockets 132 to be more particularly described hereafter. Thoughsprockets 82 and 83 with a single set of teeth would functionadequately, the double arrangement with the outer teeth removed ispreferred in order to provide support between the smooth, toothlessouter surface of each double sprocket 82 and 83 and the ends of theteeth of sprockets 132 as a bar assembly moves from top to bottom at theends of chamber 22 in a manner to be described. Each pair of sprockets82, 83 are conventionally keyed to chain drive shafts 84 and 89 suitablyjournaled for rotative movement in bearings mounted in blocks in sidepanels 120 and 12b. Suitable well known devices may be used to maintaintension in chains 80. Also, conventional means such as a variable speedmotor 270 (FIG. 9) operatively connected to shaft 84 is provided torotate the latter. Optionally includable (FIGS. 2 and 7) at thedischarge end of upper course 26 are friction wheels 96 secured to eachsprocket 83 and having resilient discs 100 for contacting the underside102 of a bar assembly 48 at each end as it moves downwardly from uppercourse 26 toward lower course 28 of chamber 22.

Means including members such as 86 (FIGS. 1-4) secured to side panels12a and 12b form opposing endless guideways 88 with such side panels oneither side of chamber 22. Portions of such members 86 are cut away asat 91 in FIG. 4 to accommodate wheels such as 135 and 140 to be furtherdescribed. Each housing 48 (FIG. 3) is provided at opposite ends withstub shafts 90 outwardly projecting from housing extension 92 towardguideway members 86 having means such as rotary followers 94 thereof forcontinuous, bar assemblysupportive movement in guideways 88 duringtravel of a bar assembly 48 along the full length of upper course 26 andlower course 28 of chamber 22. Guideways 88 stabilize each bar assemblyin the vertical direction during movement through chamber 22 and preventdisengagement of sprockets 132 from the links of unsupported chains 80as the latter rotate around in an endless path. Guideways 88 arepreferably vertically positioned such that chains 80 move underneathsprockets 132 in top course 26 and above such sprockets in bottom course28 in order to facilitate adding and removing bar assemblies to thesystem in a manner to be described.

As illustrated in FIG. 6, and preferably at a portion of guideway 88located along the lower course 28 of chamber 22 in the area generallyidentified as 108 in FIG. 1, a lower portion 110 of the guidewaydefining member is detachably mounted on each side of the chamber, via aset screw 112 and pivot pin 113, with respect to immediately adjacentportions 114 and 115. This is for the purpose of opening guideway 88 insuch area 108 for insertion of bar assemblies 48 into the system. Theparticular size 117 of the opening is preferably maintained only a fewthousandths a greater than the horizontal distance between the outerextremities of follower pairs 94 of a bar assembly 48 in order to insureaccurate aligned positioning of a bar assembly with respect to chain 80during insertion, i.e., no cocking. Guideway 88 can be made operable asjust described at any point along its length, such as, for example, atthe feed end 30 of the chamber where the assemblies 48 can be added bymerely seating bosses 146 in an opposing pair of slots 210 in wheels204, 206, to be further described.

As an important feature of the invention, rotary means generallyindicated as 120 in FIG. 3 turn parts 50 about their vertical axes 122during travel along paths 39, such means being operativelyinterconnected, as typically illustrated on the left side in FIG. 3 withthe outer strand 87 of each chain 80 of the advancing means and witheach bar assembly 48. Rotating means 120 includes shaft 74 extendingcrosswise through the rearward end of each housing 54 having spaced,spiral flight portions or worm sections 128 either integrally formedwith such shaft or separately fastened thereon, for meshing engagementwith teeth 130 of each annular pinion 64 of a bar assembly. A pair ofsmall driven sprockets 132 are pinned at 81 (FIG. 5) to extension 83which in turn is secured at 85 to opposite ends of shaft 74. Sprockets132 meshingly engage the links of strand 87 as illustrated in FIG. 4.Thus, as shaft 74 rotates, worm portions 128 in meshing engagement withteeth 130 of pinion 64 cause pinion 64 and consequently part-supportmember 56 secured thereto to rotate in unison.

Metering means generally indicated at 134 in FIG. 7 at discharge end 32control the inventory of assemblies 48 in the upper course 26 and morespecifically sequentially release bar assemblies from upper course 26 tolower course 28. Such metering means includes (FIGS. 2 and 7) a pair ofupper metering wheels 135 mounted on opposite ends of shaft 138journaled in extensions of the side panels for rotary movement. A pairof lower metering wheels 140 are on shaft 141 which is similarlyjournaled for rotary movement. Each pair of metering wheels 135 and 140have circumferentially spaced radially extending slots 143 and 145 (FIG.7) for cooperating with a boss 146 (FIG. 4) on the end of stub shaft 90at either end of bar assembly 48. Each pair of bosses first relcasablyengages a pair of slots such as 143 in upper metering wheels 135 andsubsequently in slots such as 145 in lower metering wheels 140. Drivemeans for such wheels is generally indicated as 150 (FIG. 1). In theillustrated embodiment, the prime mover for such drive means 150preferably is part of the drive train for the molding equipmentdownstream of apparatus 10, which for example, is connected directly toshaft 152 in FIG. 1. Means 150 in the illustrated embodiment includes agear box 154 driving sprocket 158 on metering wheels intermediate shaft160, which in turn drives lower metering wheel sprocket 164, whichmotion is directly transferred to upper metering wheel sprocket 165 viachain member 167 such that both wheels rotate at the same speed.Metering means 134 further includes curved, partsguide member 169 (FIG.7) between the upper and lower metering wheels situated outwardly ofchain drive sprockets 83 and extending across the width of chamber 22for supporting parts 50 as they move between the upper and lower coursesof the chamber in a manner to be described.

Gate means (FIGS. 7 and 8) generally indicated as 171 at discharge end32 on the lower course 28 of chamber 22 release parts 50 from each barassembly in a controlled manner as the latter moves along guideway 88between the upper and lower metering wheels. Movable hopper means 156(FIG. 1) beneath gate means (FIG. 8) receive parts 50 in hoppers 163 onbeing released. Hoppers 163 are mounted for rotary movement about acentral main shaft 158 which is driven from downstream moldingequipment, not shown.

Gate means 171 (FIG. 8) comprise a series of slide gates 164, one foreach path 39, with each being attached to a rod 166 reciprocable as at168 by means of pressurized air selectively admitted to cylinders 256housing a conventional piston on the end of each rod 166. Byreciprocating gate member 160 rearwardly to the left, a part 50 drops bygravity into a hopper 163 passing beneath it. Gate members 164 must bereciprocated according to a predetermined pattern in order that thelinearly arranged forwardly moving preforms in each bar assembly dropinto the circularly moving hoppers 163 at the proper time. Suchpredetermined sequence may be controlled by suitable conventionalelectric switches and multi-port solenoid valves in the air supply linefeeding each cylinder 256 of the gate means 171. Box 173 (FIG. 7) housessuch switches. A single solid gate member for releasing the entirepreform contents of a bar assembly at once may be used with alternativetypes of parts takeaway means other than those employing individualhoppers as in the illustrated embodiment.

Referring now to FIG. 2, auxiliarly drive means 174 may be provided forrotating the upper and lower metering wheel pairs 135 and 140 which isautomatically electrically actuated when the main drive from thedownstream molding equipment is de-energized, for example, due to aprocess malfunction. Such auxiliary drive means 174 comprises aconventional motor and gear box assembly 176, drive sprocket 178 anddriven sprocket 180 secured to a driven dog member 182. Member 182 andsprocket 180 together are journaled for free rotary movement about shaft160 when the main drive acting through gear box 154 is turning themetering wheels. Clutch assembly 185 of the metering wheel drive means,in operative communication with sprockets 158 and 180, determines whichof such two members will transmit motion to metering wheels intermediateshaft 160. Such clutch assembly comprises reciprocable drive dog member186 slidably keyed to intermediate shaft 160 and secured at 187 to arm188 which in turn is secured at 189 to pneumatic cylindrical assembly190. When functioning, air fed to assembly 190 through four-way solenoidvalve 192 pivots arm 188 about 191 to cause member 186 to slide eitherright or left in FIG. 10. Thus, when the downstream molding equipmentand movable hopper means 156 are operating, thereby driving shaft 152(FIG. 1) and wheels and through gear box 154, projections 194 (FIG. 2)of drive dog member 186 are engaged in opposing slots in driven dogmember 187 secured to sprocket 158. When such hopper means 156 of thedownstream molding equipment is deactivated, valve 192 is energized topneumatically reciprocate drive dog member 186 to the right in FIG. 2toward auxiliary drive means 174, bringing an alternate set ofprojections 196 into engagement in opposing cooperating slots ofauxiliary drive driven dog member 182. Motor 176 of the auxiliary drivemeans is also electrically energized under these conditions by suitableconventional means to eventually transmit power to the metering wheelsindependent of such downstream power source. Should the slots in thedriven dog members 182 and 187 be out of exact alignment withprojections 194 and 196 during such switchover, the projections willmomentarily slide on the surfaces of members 182 and 187 between theslots until alignment exists whereupon they will forcibly enter theslots to engaging position under the influence of the pressure exertedby assembly 190. When auxiliary drive means 174 functions, each gatemember 164 via suitable electric interlocks remains shut andconsequently each part 50 in a bar assembly 48 as it moves downwardlyafter being released by the upper metering wheels 135 to the lowermetering wheels 140, is dragged across the closed gate members (FIG. 1)and then drops by gravity into parts col lection means 198 (FIG. 7)beneath discharge end 32 of chamber 22 and adjacent movable hopper means156. Such parts collection means 198 may include a contoured chute 200to direct the falling parts toward a central scrap recovery andreprocessing area, not shown. With such an auxiliary drive means andparts collection system, an accumulation of workpieces in the apparatusdue to a stoppage of the main drive means for turning the meteringwheels should not occur. Parts 50 can continue to be supplied in thenormal manner to the system until the downstream equipment is clearedand ready to accept conditioned parts once again.

At the feed end 30 of chamber 22 infeed means generally indicated as 202(FIG. 9) admit each bar assembly 48 at regular intervals to the partscharging station and then to upper course 26 of chamber 22 in a mannerto be described. Infeed means 202 comprises a pair of laterally spacedescapement wheels 204 and 206 journal mounted such as at 203 to mainchain drive shaft 84. Each escapement wheel 204, 206 has forwardlydirected, spaced radially extending slots 210 (FIG. 1) formed in theperiphery thereof similar to those in the metering wheels at the otherend of the apparatus. The same previously described boss 146 at each endof a bar assembly 48 seats in slots 210 in each of the escapement wheels204 and 206 when the bar assembly is being held at the feed end 30during loading. Power means generally indicated in FIG. 9 as 212 areprovided for cyclically rotating wheels 204 and 206 and includes limitswitch 214 (FIG. 7) conventionally electrically interlocked withindexing drive mechanism or intermitter 216 (FIG. 9). Such anintermitter is commercially available and conventionally houses cam andgearing mechanisms which define the amount of rotary movement per cycleand includes driven output shaft 218 for rotating indexing driveintermediate shaft 220 journaled for rotation in suitable bearingblocks. Pinion 222 at the opposite end of shaft 220 cooperates with asuitable chain or belt member which drives escapement wheel sprocket 224which is secured to escapement wheel 204. Thus, though chain drive mainshaft 84 is continuously rotating via power input from motor 89,escapement wheel 204 cyclically rotates with respect to shaft 208independent of movement of the latter. A similar drive assembly on theright hand side in FIG. 9 as just described is employed to rotateescapement wheel 206 from intermitter 216 and shaft 220. Thus. limit ormicro-switch 214 by contact of its arm 226 (FIG. 7) with each barassembly passing between the upper 135 and lower 140 metering wheelselectrically activates the motor portion of intermitter 216 to rotateoutput shaft 218 a preset amount sufficient to lift an empty barassembly from the right hand end of lower course 28 upwardly viaengagement of bosses 146 in slots 210 in the escapement wheels into theloading station at feed end 30.

In FIG. 11, molding station generally indicated as 228 includes opposingmold sections 230a and 230b closable on each other in conventionalmanner to form cavity 232 having a periphery conforming to that of ahollow article, such as bottle 241. Cavity 232 though illustrated in anupside-down position may alternatively be positioned right-side up.Stretch and blow assembly 234 cooperates with sections 230 and includesan extendable stretch rod member 236 having a shoe portion 238 on itsforward end and is reciprocably mounted by suitable means in an openingat one end of cavity 232. Rod member 236 has an interior passage 237opening into air outlet ports 240 for admitting air under pressure tothe interior of a molded part 50 either during or subsequent tostretching the closed end of such part 50 against the base of cavity232.

In operation, previously molded, preforms 50 each having an overallcontour which is generally symmetrical about its axis 122 and preferablyhaving a closed end 243 and a finish portion 242 which in theillustrated embodiment includes spiral threads (FIG. 4) and step 60immediately below such threads, are provided to apparatus 10. Preforms50 may be at room temperature or alternatively and preferably will havebeen discharged from an injection or blow molding station a few momentsbefore and consequently will be at a somewhat elevated temperature. Inany event, it is desired to bring the thermoplastic material preferablyconstituting body portion 244 of each preform 50 to within a temperaturerange at which substantial molecular orientation can be developed onstretching. Such range may broadly be defined as that from the glasstransition temperature of the polymer forming the ther moplasticmaterial at the lower end of the range up to a temperature at which meltflow of the polymer can occur. Within this broad range, it is preferredto develop such substantial molecular orientation at temperatures from25 to 100F. above the glass transition temperature of the polymer toavoid the need for excessively high forces on the one hand to stretchthe polymer at the lower end of the broad range and on the other hand,to avoid rapid relaxation of stresses developed on stretching at theupper end of the broad range. Apparatus 10 has been found especiallyuseful when body portion 244 though varying in temperature through itsthickness, does have portions toward its interior which are attemperatures greater than those at which substantial molecularorientation can be developed, and accordingly it is necessary todecrease such temperature(s) prior to reshaping the preform into afinished molecularly oriented article.

Preforms 50 are loaded at the charging station at feed end 30, eitherautomatically or manually, into the sockets formed by each part-supportinsert 56 of a bar assembly 48, while each such assembly temporarilydwells, usually for a matter of a few seconds, in the loading station,i.e., at substantially a 12:00 oclock position with respect toescapement wheel 204, FIG. 1. As indicated in FIG. 4, each loadedpreform is supported in suspended relationship against collar 58 ofinsert 56, with the preforms in a particular bar assembly forming alinearly oriented collection of same extending perpendicular to thecenterline of chamber 22 with their lengthwise dimensions (i.e., alongaxis 122) substantially normal to the direction of extension of panels38 of the heat transfer assemblies along the chamber. Though preforms 50might be positioned in the system with closed ends 243 uppermost, thereverse is preferred both to minimize handling in subsequent operationsas will be apparent hereafter, and to avoid sagging of the weight of thebody portion 244 back on the finish portion 242 when the preforms are atelevated temperature.

After each bar assembly 48 has been loaded, it being understood thateach position therein need not be filled, it is released from theloading position by rota' tion of escapement wheels 204 and 206, suchthat bosses 146 which had been seated in engagement with the walls ofslots 210 are free to move out of such slots under the influence ofcontinuously advancing chains and the sprockets 132 at opposite ends ofeach bar assembly which are seated in the outer strand 87 of suchchains. Thus, as a bar assembly starts along the initial portion ofchamber 22, no relative movement exists between it or any or itscomponents and the chains conveying it forward toward the discharge endof the assembly. Each assembly is being propelled forward relativelyfast at this point in the process at the same speed as that of chains80. No heat transfer to any substantial extent with respect to preforms50 occurs dur ing this portion of the process, and as a matter of fact,depending on residence time requirements, the heat transfer unit 21closest feed end 30 may be eliminated altogether or medium circulationthrough an existing such assembly merely shut off until necessary.

When the most recently released bar assembly reaches the prior one inchamber 22 under the conveying influence of chains 80, it gently strikesthe rear surface thereof which serves as an abutment against furtheradvancement at chain speed, and at this point, relative movementcommences between sprockets 132 of rotating means and the continuouslymoving chains, while roller followers 94 rollingly support the loadedbar assembly in guideways 88, as has occurred from initial introductionof the loaded assembly into the system. The ring of teeth of sprockets132 enter and exit the spaces within the links of the outer strands 87of advancing chains 80 to thereby rotate shaft 74 and wonn sections 128which in turn mesh with the teeth of each pinion 64 to rotate the latteras well as partsupport carrier 56 keyed thereto which, as described, isfrictionally holding a preform 50 on collar 58. Each preform then isrotated with carrier 56 with respect to its bar assembly 48 by suchmotion of shaft 74 about its vertical axis 122 while supported andsuspended in an assembly 48 as the latter continues to be conveyedforwardly toward the discharge end of the apparatus. The actual rotaryspeed of a preform is the difference between the peripheral speed ofmetering wheels 135 and 140 which is synchronized with that ofdownstream equipment as will be further described (or the speed at whichassemblies 48 are moving) and the speed of the moving chain, for formernecessarily being less than the latter to permit such rotary movement.Accordingly, if it is desired to change the rotary speed of the preformsduring conditioning, this can be done by changing the chain or meteringwheel speed or both depending on whether it is desired to rotate fasteror slower. Preferably, chain speed is changed via variable speed drivemotor 270 since this avoids adjusting metering wheel speed and thus thatof downstream molding equipment which can remain constant. It is duringthis portion of the path of travel of the preforms where rotary movementoccurs and which usually represents about of the overall length ofchamber 22, that the intended design heat conditioning of the preformstakes place.

If it is desirable, for example for equipment layout purposes, to setapparatus on an incline, i.e., canted upwardly, frictional force may begenerated to prevent a shaft 74 from rotating in place on chains 80 as abar assembly 48 is being freely conveyed forwardly and upwardly at chainspeed prior to abutment against the previous assembly, by merelymanipulating adjusting screw 73 to create whatever force is desired forurging shoe member 68 against collar 72 which is fixed to shaft 74.

As each assembly 48 moves forwardly, the rotating body portion 244 ofeach of the plurality of preforms 50 moving in parallel passes between apair of adjacent heat transfer panels 38 along path 39. It is preferredthat each preform in a bar assembly be assigned to a single pathalthough it is within the scope of the invention to widen the paths andpass two or more preforms between horizontally adjacent panels. Whenthis is done, however, the time to bring a preform at a given startingtemperature pattern to the desired end temperature will be increased fora constant temperature heat sink and consequently the length of theapparatus would have to be increased to provide more heat transfersurface. Also, if the number of preforms per path or channel isincreased excessively, in a cool-down process heat will be transferredfrom one preform to the next and then eventually to the panels ratherthan the preferred more direct approach. During movement of the partsthrough the apparatus, it should be noted that in the embodiment of thedrawings, finish portion 242 of each preform which does not require anyfurther reshaping, is snugly confined within its socket 56 above the topof panels 38 (FIG. 2) and consequently is shielded from exposure to thepanels during advancing movement of each bar assembly. As a matter offact, the atmosphere around the finish portions 242 may have a coolingand hardening effect on the plastic, since it is above the panels 38 andrelatively free to circulate to the surroundings via the open ends andbottom of the apparatus. Also, when the various parts of assemblies 48are formed of a low heat conductive material such as the previouslydescribed phenolic plastic, heat transfer back to finish portion 242,which is preferably cooler at the start of the process than body portion244, is minimized.

Rotative movement of each preform 50 as it traverses path 39 averagesout exposure of the thermoplastic material of each body portion to thepanel surface and eliminates edge effects otherwise present along theleading and trailing surfaces of the preforms. Every point in each bodyportion 244 is exposed over a period of time to a uniform temperatureheat sink provided by the three individually closely controlled heattransfer assemblies 21 to bring the thermoplastic material to within thetemperature range at which substantial molecular orientation occurs onstretching. In a cool-down process, this results overall in heat beingremoved by radiation from the preforms to the surface of panels 38 andthen to the particular medium circulating through channels 40 which may,for example, be oil or water. In a cool-down process, the heat transfermedium nevertheless should be heated to about 150 to 220F., to controlthe temperature gradient between inner and outer surfaces of the preformbody 244, a smaller gradient being desirable to facilitate the ease bywhich optimum orientation temperature is developed in the material.Conventional equipment well known to those in the art may be utilized tocontrol the temperature of the medium, for example, to within about 11F.between the inlet and outlet to a particular bank of panels 38. In theillustrated embodiment, oil is fed from a manifold in parallel to thebottom of each of eleven panels of a heat transfer assembly, with flowbeing upwardly through passages 40 of each panel 38 to a second manifoldwhere discharging oil is collected in parallel and piped back to thereservoir. Three such arrangements are employed in the illustratedembodiment with conventional temperature control instrumentation on eachto permit varying, in a controlled manner, the temperature of the mediumof one assembly versus another, if necessary.

When a bar assembly reaches the end of the single pass heat transferzone, i.e., at the left end of panels 38 in FIG. 7, the continuouslyturning upper metering wheel pair rotate downwardly through cutawayportions 91 in guideway defining members 86 to bring slots 143 intomomentary engagement with followers 146 on either end of the heattransfer zone. The pitch 250 (FIG. 7) or centerline distance betweenadjacent slots 143 is equal to the centerline distance between bosses146 in two abutting bar assemblies, to provide for precise engagement ofsuccessive slots and bosses during rotation of wheels 135. The samepitch distance between slots and bosses is likewise maintained for thesame reason with wheel pairs and 204. As a particular pair of slotscontaining bosses 146 turns through a portion of the lower arc in FIG. 7of wheels 135, the engaged bar assembly is metered forward and freed bythe continued upward movement of the slot pair. As the followers exit aslot pair 143, in order to prevent each bar assembly from free fallingby gravity between the top and bottom courses of chamber 22 and therebypossibly distort the soft parts 50 therein, discs 100 of friction wheels96 engage the underside 102 of each assembly (FIGS. 2 and 7) urgingfollowers 94 outwardly against the surface of the outer guideway formingmember, thereby carefully but relatively rapidly to avoid preform sag,guiding the assembly between the courses at chain speed. As eachassembly is thus turned downwardly, preforms 50 abut guide member 169which prevents them from sliding out of the bar assemblies as a resultof such upending turning movement.

As the bar assembly approaches bottom course 28 of chamber 22, eachpreform passes along guide member 169 and gradually assumes an invertedposition while partially sliding out of its opening in the bar assemblyuntil the surface defining the open end of the top of the finish comesinto contact with the upper surface of a reciprocable slide gate 164.Accordingly, each preform is temporarily supported (FIG. 7) on end in anupended position while still in a bar assembly continuously movingwithout interruption except now in an opposite rearward direction.

Considering now the embodiment of FIG. 8, when the hoppers for acceptingthe preforms are continuously moving in a circular path, and thelinearly arranged performs in a bar assembly are moving in a lineardirection, the preforms should be released by gate members 164 accordingto a predetermined drop sequence, i.e., as close as possible to theprecise moment the axis 122 of a preform 50 is coincident with that of ahopper 163. In other words, as bar assembly 48 moves forward in thedirection of arrow 252 in FIG. 8 radially to the rotary path of hoppers163, at a given time a particular hopper will be under a particularlinearly arranged preform depending on the position of the bar assembly.The drop sequence can be readily specified for any particularcombination when the speeds of the bar assemblies and hoppers are known,and it may turn out for certain combinations that two or more preformsshould be dropped simultaneously. Accordingly, when the hopper for apreform resting on a particular gate member 164 in the illustratedembodiment is beneath such gate member, the latter is automaticallyreciprocated rearwardly via the piston and cylinder 256 so as to allowthe preforms to drop by gravity out of the bar assemblies intoindividual hoppers. Specification of optimum drop pattern is importantfor the linear-rotary movement of the components of the illustratedembodiment, since the further away the axis of a preform is from that ofits hopper 163 at the precise moment of drop, the greater the necessarywidth in the direction (FIG. 8) ofa hopper, and as hopper width isincreased, so likewise is the tendency for the soft, dropped part to tipand hang up in the throat at the lower end of the funnel-shaped hopper163.

The temperature-conditioned preforms are then transferred, eitherautomatically or manually or by combinations thereof, to molding station228, FIG. 11. Sections 230 are closed around it, stretch-blow assembly234 brought into position such that rod member 236 is inserted into theopen end and then actuated by suitable means to increase the length ofbody portion 244 as at 247 via forced contact of foot 238 against theinner surface of the closed end to thereby stretch the plastic anddevelop longitudinal or axial orientation. In the preferred procedure ofthe illustrated embodiment, after contact (or just prior thereto) of theouter surface of the closed end of the preform with the opposing wall ofthe mold cavity 232, air under pressure is admitted through ports 240 toexpand it outwardly in a radial direction against the cavity walls toform the article and develop radial orientation. Axial and radialstretching, however, may be carried out simultaneously under certainconditions, e.g., when pronounced axial orientation is felt unnecessary.

Returning now to the bar assemblies, after the parts are released, andafter having been metered out of the area between upper and lower wheelpairs 135 and 140 by the latter, they are recycled via chains andsprockets 132 at chain speed in the opposite direction along open-bottomlower course 28 to feed end 30. Metering action via lower wheels 140 isthe same as previously described for the upper pair 135. Preferably nobackup of loaded assemblies in the turn between the two pairs is allowedduring operation in order to avoid having the soft, deformable parts sagunder their own weight which tends to occur when the preforms areoriented other than in a vertical attitude. In so moving rearwardly eachbar assembly continues to be supported in guideway 88 via rollers 94.

As previously indicated, micro-switch 214 positioned in the path ofdownwardly turning bar assemblies at the discharge end of the assemblybetween the upper and lower metering wheel pairs electrically energizesintermitter 216 which causes escapement wheels 204, 206 to turn throughan arc of about 180 so as to revolve the next empty bar assembly viaengagement with radial slots 210 and bosses 146 upwardly from beneaththe heat transfer panels into position at the loading station forreceipt of additional preforms to commence another cycle. Thus, duringan operating cycle of a bar assembly it traverses a closed path withinthe apparatus 10.

Regarding the variable conditioning time feature, the continuous rate ofdischarge of parts from the system via synchronously operating meteringwheels and is preferably set slightly less than the feed rate such thatan accumulation of successive loaded bar assemblies exists in the heattransfer zone as generally indicated at 249 in FIG. 1, preforms, forsimplicity purposes, not being shown in FIG. 1 in each and every barassembly 48 in upper course 26. The portion of the total length of paths39 occupied by the accumulation 249 of loaded bar assemblies for a givenset of feed and discharge conditions may be considered to be theeffective heat transfer length of the total zone within chamber 22.Similarly, a reservoir of empty assemblies is established at the end oflower course 28 adjacent and beneath the charging station as illustratedat 250 in FIG. 1. The latter may be accomplished by manually addingempty assemblies to the system via the operable portion of the guidewaypreviously described with reference to FIG. 6. Thus, in area 108rearwardly of the empty bar assembly reservoir, pivotable section 110 isreleased downwardly and empty bar assemblies then inserted upwardlythrough the opening into place such that followers 94 are seated inguideway 88, whereupon the assembly is manually pushed away toward theloading station to be then conveyed forward as previously described viaengagement between sprockets 132 and the links of chains 80. Such addedbar assemblies then become part of the accumulated reservoir and areeventually turned up into the loading position by the escapement wheels.Thus, by varying the effective length of the path of exposure ofassemblies 48 to panels 38 (i.e., 249 in FIG. 1) by manipulating emptyassemblies, residence time in chamber 22 of successive groups of partscan be changed while keeping the continuous discharge rate of parts fromthe assembly and the temperature of the heat transfer panels essentiallyconstant, and maintaining as well the fixed position of the parts withrespect to each other both along and across the chamber. Suchvariability avoids processing disruptions which occur while waiting forequilibrium to be re-established when it is elected to vary heattransfer by changing the temperature of the conditioning medium. Whenthe rate at which empty bar assemblies are metered from reservoir 251into the loading station equals the continuous rate of metering out ofarea 249, a steady state condition exists. Should the startingtemperature of the preforms being fed to the system change, for example,such that it is desired to change temperature conditioning timeaccordingly, a conventional electrical override circuit may be manuallyenergized to cycle intermitter 216 independently of micro-switch 214.Increasing cycle frequency in this way increases the rate at which barassemblies are presented to and discharged from the charging stationfrom reservoir 251 such that it exceeds the undisturbed rate ofcontinuous metering of loaded bar assemblies out of the heat transferzone, thereby increasing the number of and therefore the residence timeof bar assemblies and of subsequently introduced parts in such zone. Itmay be necessary to temporarily interrupt the feed to the system whenempty bar assemblies are being added to the upper course in this way, oralternatively, they might be quickly cycled through the charging stationwhile the group of preforms which will occupy the next assembly arebeing collected. In this latter respect, interruption of upstreamprocessing steps is avoided. When the reverse is done, i.e., the rate ofmetering of bar assemblies into the zone is less than the rate ofcontinuous metering out of the zone, the eventual length of accumulation249 is decreased at the expense of an increase at 251 and therefore theresidence time of bar assemblies and of subsequently introduced parts inthe heat transfer zone 249 is reduced.

The wall of the body of preforms 50 may contain uneven thicknesssections in the circumferential direction, as illustrated by opposingthick and thin portions 253 and 255 respectively in FIG. 4, formed, forexample, when the preforms have been molded by blowing. Preforms whichhave just been blow molded possess a particular temperature pattern,i.e., an outer layer or skin of the body portion which had been indirect contact with a chilled mold surface is at a lower temperaturethan the portions of the wall inward of such outer skin, and since thinportion 255 will have been cooled more than thick portion 253, theoverall temperature of the former will be lower than that of the latter.In shaping a hollow molecularly oriented article from such preformswherein improved uniformity of wall thickness is desirable, thetemperature of the body portion should be reduced before stretching asdescribed, but in so doing, it is important to maintain a relativetemperature difference between opposing thick 255 and thin 253 sectionsin the uneven wall thickness preform. When such difference exists, thin,cooler section 253 will stretch less than the Opposing thick section 255during reshaping in the molding station thereby improving the relativeevenness in wall thickness in the finished article and compensating forthe unevenness in the initial preform. Stated differently, duringconditioning in the apparatus of the invention of a preform having awall thickness material distribution as illustrated in FIG. 4,development of a uniform temperature in the body portion during passagethrough the conditioning zone is purposely avoided in order to maintaina temperature differential between thick and thin sections of the bodyduring subsequent stretching and blowing. With an even temperature inboth thick and thin sections, the thinner section having a melt strengthless than the thicker stretches more and is reduced even further inthickness during forming of the article, this severely hinderingsubsequent performance of the article in use especially when in the formof a container such as a bottle. Such maintenance of a temperaturegradient, however, is unnecessary and preferably avoided in favor of aconstant temperature throughout when the thickness of the preform wallis substantially even in the circumferential direction.

EXAMPLE Thermoplastic material comprising a polymer of /30 weightpercent acrylonitrile/styrene was extruded at a temperature of about475F. through a conventional annular orifice in the usual way as shownin US. Pat. No. 3,754,851 to form a tubular parison. Sections thereofwere thereafter enclosed in a blow mold and expanded outwardly againstcooled walls at about 40F. of an internal cavity to form preforms of thetype illustrated at 50 in FIG. 4, the uneven thickness being determinedby sectioning the preforms and noting wall distribution. After retentionin the mold for a few seconds to allow the plastic of at least an outerskin portion (and generally also the portion just beneath such skin) toset, the parts were ejected and waste flash immediately removed. Thepreforms were then immediately inserted in holders and cylindricalshrouds placed around them spaced outwardly from the walls thereof, forthe purpose of creating a quiescent environment undisturbed by thesurroundings, and in order to permit the plastic through the full bodywall to come to a temperature equilibrium wherein no substantialvariation through the thickness existed. In so doing, it was expectedthat the chilled outer surface portions would be slowly conductivelyreheated by the adjacent, inner high temperature wall portions with thelatter accordingly falling in temperature until eventually the full wallthickness would be at a temperature which did not vary appreciably fromouter to inner surface. The shrouds were periodically removed fromaround the preforms and the latter rotated in front of an infra-redsensor of a model 4OIOS temperature indicating system manufactured byWilliamson Corp., 1152 Main Street, Concord, Mass. Surface temperaturereadings thus obtained increased slowly to an average of about 285F.after 3.5 min., such temperature having been previously determined asbeing within the range at which substantial molecular orientation couldbe developed in the nitrile-based thermoplastic material of thepreforms. When such temperatures were reached, the preforms wereimmediately enclosed in a mold and stretched and blown into bottles suchas at 241 in FIG. 1 l, which were intended to be used to package liquidsunder pressure. The blown bottles thereafter were filled with water,capped and dropped on a flat surface from a height of 18 inches. Othersfilled and capped in the same manner were subjected to an incrementallyincreasing pressure in the space above the liquid until the bottle burstat which point pressure was noted. This run and tests are consideredherein to serve as a control.

Preforms manufactured as just described, were passed through theapparatus of the invention with the temperature of the heat transfermedium controlled at about l60F. and immediately thereafter stretchedand blown into bottles. The type of polymer, preform shape and totalweight and mold shape were identical with the control.

The bottles formed initially were sectioned in the area of greatestdiameter perpendicular to the bottle axis and the wall thickness, asmeasured by micrometer. determined to vary substantially from side toside, typically from 50 to 60%. The time of heat transfer exposure tothe heating panels of preforms being continuously conditioned in thisway was then gradually reduced over a period of time by slowing the rateat which empty assemblies are presented to the loading station, thusdecreasing the effective length of loaded bar assemblies in theconditioning zone. As residence time was empirically decreased in thismanner, circumferential variability in wall thickness in the sectionedbottles decreased to a level of -15%. When such conditions of minimumvariability were reached, burst and impact tests were carried out aspreviously. The results were as follows:

With respect to the run providing minimum finished bottle wall thicknessvariation according to the invention, as indicated, the initialtemperature profile of the suspended preform body is such that the outersurface temperature is relatively low and increases through the walltoward something somewhat below the initial extrusion temperature at theinner surface, with the average overall wall temperature beingsubstantially greater than that desired for developing substantialorientation. It is postulated that the preform with such a profile andwall thickness pattern initially liberates equal heat at the beginningof cool-conditioning. Then as heat is liberated, the thin part with lessheat capacity becomes cooler with the thick part, though loosingtemperature. remaining hotter because of its greater heat capacity, sothat before such pattern can change by the body remaining exposed toolong to the heat sink, it is stretched and blown to achieve a finishedarticle of substantially uniform thickness without overly thin spotswhich create failure sites when impacted and pressurized. The averageoverall temperature gradient between opposing thick and thin sectionsjust prior to stretching and blowing is postulated to be from 6 to 20 F.

Thus the technique of the instant invention wherein a temperaturedifferential is maintained between thick and thin portions of an uneventhickness preform to be molded into a container is shown to be superiorto the technique of equilibrating the full wall thickness to the sametemperature prior to molding.

Various modifications and alterations of the invention will be readilysuggested to persons skilled in the art. It is intended therefore, thatthe foregoing be considered as exemplary only and that the scope of theinvention be ascertained from the following claims.

What is claimed is:

1. Apparatus for temperature-conditioning elongated b. heat transferassemblies spaced from each other and extending along said chamberdefining generally parallel paths for said parts;

c. a plurality of bar assemblies having means to hold said parts in saidpaths with their lengthwise dimensions substantially normal to thedirection of extension of said heat transfer assemblies;

d. means for advancing said bar assemblies through said chamber; and

e. rotating means operatively interconnected with the advancing meansand the bar assemblies for turning the parts about their lengthwisedimensions during travel along said paths.

2. The apparatus of claim 1 wherein said chamber has a feed and adischarge end and including gate means at the discharge end forreleasing the parts from the bar assemblies.

3. The apparatus of claim 1 wherein said sections include a floor memberon which said assemblies are mounted, said floor member dividing saidchamber into an upper and a lower course, said lower course being opento the surroundings along its length.

4. The apparatus of claim 1 wherein said sections include removablecover members.

5. The apparatus of claim 1 wherein said heat trans fer assembliescomprise panels containing flow channels and means for circulating aheat transfer medium through said channels.

6. The apparatus of claim 2 including hopper means beneath the gatemeans for accepting the released parts.

7. Apparatus for temperature-conditioning elongated molded parts whichcomprises:

a. wall sections defining a horizontally extending chamber;

b. a plurality of heat transfer panels spaced from each other andextending along said chamber defining generally parallel paths for saidparts;

c. means for circulating a heat transfer medium through said panels;

d. a plurality of bar assemblies mounted for movement along the chamberabove the heat transfer panels, each bar assembly comprising:

i. a housing having a series of horizontally spaced openings formedtherein vertically aligned with said paths;

ii. an annular pinion seated in each opening;

iii. a part-support insert secured to said pinion;

e. means for advancing said bar assemblies through said chamber; and

f. rotating means operatively interconnected with the advancing meansand the pinion of each bar assembly for turning the part-support insertsas the bar assemblies are moved through the chamber by the advancingmeans.

8. The apparatus of claim 7 including:

i. members forming opposing guideways in said wall sections on eitherside of said chamber; and

ii. means at opposite ends of each housing for bar assembly-supportivemovement in said guideways during travel of each bar assembly throughthe chamber.

9. The apparatus of claim 8 wherein at least a portion of one of saidmembers is detachably mounted with respect to an immediately adjacentportion for opening said guideway.

10. The apparatus of claim 7 wherein said housing, pinion andpart-support insert are formed of a low heat conductive material.

11. The apparatus of claim 10 wherein said low heat conductive materialis phenolic plastic.

12. Apparatus for temperature-conditioning elongated molded parts whichcomprises:

a. wall sections defining a horizontally extending chamber;

b. a plurality of heat transfer panels spaced from each other andextending along said chamber defining generally parallel paths for saidparts;

c. means for circulating a heat transfer medium through said panels;

d. a plurality of bar assemblies mounted for movement along the chamberabove the heat transfer panels, each bar assembly including annularpartssupporting and rotating mechanisms;

e. means for advancing said bar assemblies through said chamber; and

f. rotating means for turning said part-supporting and rotatingmechanisms during movement of the bar assemblies through the chamber,said rotating means comprising:

i. a shaft extending through each bar assembly;

ii. worm sections on said shaft in meshing engagement with theparts-supporting and rotating mechanisms; and

iii. sprockets on the opposite ends of the shaft rotatably engaging theadvancing means.

13. The apparatus of claim 12 wherein each bar assembly includes a brakemechanism acting on a portion of the shaft.

14. The apparatus of claim 12 wherein said advancing means comprisesdual, endless double stranded chains extending horizontally through andsituated on opposite sides of said chamber and dual double sprockets forsaid chains at opposite ends of the chamber.

15. The apparatus of claim 13 wherein said brake mechanism includes ashoe in forced surface contact with said shaft portion and includingregulating means for adjustably urging the shoe against the shaftportion.

16. Apparatus for temperature-conditioning elongated molded parts whichcomprises:

A. wall sections defining a horizontally extending chamber having a feedend and a discharge end, said sections including a floor member dividingsaid chamber into an upper and a lower course;

B. heat transfer assemblies spaced from each other and extending alongsaid chamber defining generally parallel paths for said parts;

C. a plurality of bar assemblies for supporting said parts in verticalposition between said heat transfer assemblies;

D. means for advancing said bar assemblies through said chamber; and

E. metering means for sequentially releasing bar assemblies to thedischarge end of the chamber.

17. The apparatus of claim 16 wherein said metering means comprises:

a. upper and lower metering wheels having radially extending slotstherein;

b. a boss at opposite ends of each bar assembly for engagement in saidslots; and

c. drive means for rotating said metering wheels.

18. The apparatus of claim 16 wherein said means for advancing the barassemblies comprises:

a. endless chains horizontally opposite each other extending along saidchamber;

b. sprockets for said chains mounted for rotary movement on shafts atthe feed and discharge ends of said chamber; and said metering meansincludes:

c. a pair of upper metering wheels at the discharge end of the uppercourse mounted on one of the shafts of the bar assembly advancing meansand spaced from the sprockets thereon, said wheels having radiallyextending slots formed therein;

. a pair of rotatably mounted lower metering wheels at the discharge endof the lower course, said lower metering wheels having radiallyextending slots formed therein;

e. a boss at each end of each bar assembly for successively engaging theslots in the upper and lower metering wheels;

f. a curved, parts-guide member between the upper and lower coursesoutwardly of the sprockets and extending across said chamber; and

g. means for rotating said metering wheels in synchronism with eachother.

19. The apparatus of claim 17 including movable hopper means for theparts beneath the discharge end of the chamber.

20. The apparatus of claim 18 wherein said means for advancing the barassemblies includes:

i. members forming opposing guideways in said wall sections on eitherside of said chamber;

ii. rotary followers at opposite ends of each housing for barassembly-supportive movement in said guideways;

iii. friction wheels at the end of the upper course at the discharge endof the chamber associated with said sprockets for contacting each barassembly as it moves from the upper to the lower course to urge saidfollowers outwardly against surface portions of said guidewayformingmembers.

21. The apparatus of claim 19 wherein said movable hopper means anddrive means for rotating the metering wheels are synchronized.

22. Apparatus for temperature-conditioning elongated molded parts whichcomprises:

A. wall sections defining a horizontally extending chamber having a feedend and a discharge end, said sections including a floor member dividingsaid chamber into an upper and a lower course;

B. heat transfer assemblies spaced from each other and extending alongsaid chamber defining generally parallel paths for said parts;

C. a plurality of bar assemblies adjacent said heat transfer assembliesfor supporting said parts in vertical position between said heattransfer assemblies',

D. means for advancing said bar assemblies through said chamber; and

E. infeed means for sequentially releasing bar assemblies at regularintervals to the upper course of the chamber.

23. The apparatus of claim 22 wherein said infeed means comprises:

a. a pair of rotatably mounted escapement wheels at the feed end of thechamber having circumferentially spaced, radially extending slots;

b. a boss at each end of each bar assembly for engagement in said slots;and

c. power means for cyclically rotating said escapement wheels.

24. The apparatus of claim 22 wherein said means for advancing the barassemblies comprises:

a. endless chains horizontally opposite each other extending along saidchamber;

b. sprockets for said chains on shafts mounted for rotary movement atthe feed and discharge ends of said chamber; and said infeed meansincludes:

c. a pair of excapement wheels at one end of the upper course at thefeed end of the chamber and mounted on the shaft at the feed end of themeans for advancing the bar assemblies, said wheels having radiallyextending slots fored therein;

d. a boss at each end of each bar assembly for engaging the slots in theescapement wheels; and

e. power means for cyclically rotating said escapement wheels.

25. The apparatus of claim 24 wherein said power means includes anintermitter.

26. Apparatus for temperature-conditioning elongated molded parts whichcomprises:

a. wall sections defining a horizontally extending chamber, said chamberhaving a feed and a discharge end;

b. heat transfer assemblies spaced from each other and extending alongsaid chamber defining generally parallel paths for said parts;

c. a plurality of bar assemblies adjacent said heat transfer assembliesfor supporting said parts in vertical position between said heattransfer assemblies;

d. means for advancing said bar assemblies through said chamber;

e. gate means at the discharge end for releasing the parts from the barassemblies;

f. movable hopper means beneath the gate means for accepting thereleased parts;

g. metering means for sequentially releasing bar assemblies to thedischarge end of the chamber;

h. auxiliary drive means for turning the metering means when the movablehopper means stops; and

i. parts collection means beneath the discharge end and adjacent themovable hopper means.

27. The apparatus of claim 26 including infeed means for admitting eachbar assembly to the chamber at regular intervals.

28. The apparatus of claim 26 wherein the metering means comprises:

i. drive means for turning a pair of metering wheels;

and including:

ii. a clutch assembly in operative cooperation with the drive means forthe metering wheels and the auxiliary drive means.

29. Apparatus for temperature-conditioning elongated molded parts whichcomprises:

A. wall sections defining a horizontally extending chamber having a feedend and a discharge end, said sections including a floor member dividingsaid chamber into an upper and a lower course;

B. a plurality of heat transfer panels spaced from each other andextending along said chamber defining generally parallel paths for saidparts;

C. means for circulating a heat transfer medium through said panels;

D. a plurality of bar assemblies mounted for movement along the chamberabove the heat transfer panels, each bar assembly comprising:

i. a housing having a series of horizontally spaced openings therein invertical alignment with said paths;

ii. an annular pinion seated in each opening;

iii. a part-support insert secured to said pinion;

E. means for advancing said bar assemblies through said chambercomprising:

i. dual endless double stranded chains extending horizontally throughand situated on opposite sides of said chamber, and

ii. dual double sprockets for said chains at opposite ends of thechamber;

F. rotating means for turning each pinion comprising:

i. a shaft through each bar assembly;

ii. worm sections on said shaft in meshing engagement with the annularpinions; and

iii. sprockets on opposite ends of each shaft for engaging one of thestrands of the double stranded chains;

G. members forming opposing guideways in said wall sections on eitherside of said chamber;

H. means at opposite ends of each housing for bar assembly-supportivemovement in said guideways during travel of each bar assembly throughthe chamber;

. metering means for sequentially releasing bar assemblies to thedischarge end of the chamber, said metering means comprising:

i. upper and lower metering wheels having radially extending slotstherein;

ii. a boss at each end of the shaft of each bar assembly for engagementin said slots; and

iii. drive means for rotating said metering wheels;

1. movable hopper means for the parts beneath the discharge end of thechamber;

K. gate means between the lower metering wheel and the movable hoppermeans for releasing the parts from the bar assemblies;

L. infeed means for releasing each bar assembly at regular intervals tothe upper course of the chamber, said infeed means comprising:

i. a pair of rotatably mounted escapement wheels at the feed end of thechamber having circumferentially spaced, forwardly directed, radiallyextending slots for said bosses; and

ii. power means for cyclically rotating said escapement wheels;

M. auxiliary drive means for turning the metering wheels when themovable hopper means stops; and

N. parts collection means beneath the discharge end adjacent the movablehopper means.

1. Apparatus for temperature-conditioning elongated molded parts whichcomprises: a. wall sections defining a horizontally extending chamber;b. heat transfer assemblies spaced from each other and extending alongsaid chamber defining generally parallel paths for said parts; c. aplurality of bar assemblies having means to hold said parts in saidpaths with their lengthwise dimensions substantially normal to thedirection of extension of said heat transfer assemblies; d. means foradvancing said bar assemblies through said chamber; and e. rotatingmeans operatively interconnected with the advancing means and the barassemblies for turning the parts about their lengthwise dimensionsduring travel along said paths.
 2. The apparatus of claim 1 wherein saidchamber has a feed and a discharge end and including gate means at thedischarge end for releasing the parts from the bar assemblies.
 3. Theapparatus of claim 1 wherein said sections include a floor member onwhich said assemblies are mounted, said floor member dividing saidchamber into an upper and a lower course, said lower course being opento the surroundings along its length.
 4. The apparatus of claim 1wherein said sections include removable cover members.
 5. The apparatusof claim 1 wherein said heat transfer assemblies comprise panelscontaining flow channels and means for circulating a heat transfermedium through said channels.
 6. The apparatus of claim 2 includinghopper means beneath the gate means for accepting the released parts. 7.Apparatus for temperature-conditioning elongated molded parts whichcomprises: a. wall sections defining a horizontally extending chamber;b. a plurality of heat transfer panels spaced from each other andextending along said chamber defining generally parallel paths for saidparts; c. means for circulating a heat transfer medium through saidpanels; d. a plurality of bar assemblies mounted for movement along thechamber above the heat transfer panels, each bar assembly comprising: i.a housing having a series of horizontally spaced openings formed thereinvertically aligned with said paths; ii. an annular pinion seated in eachopening; iii. a part-support insert secured to said pinion; e. means foradvancing said bar assemblies through said chamber; and f. rotatingmeans operatively interconnected with the advancing means and the pinionof each bar assembly for turning the part-support inserts as the barassemblies are moved through the chamber by the advancing means.
 8. Theapparatus of claim 7 including: i. members forming opposing guideways insaid wall sections on either side of said chamber; and ii. means atopposite ends of each housing for bar assembly-supportive movement insaid guideways during travel of each bar assembly through the chamber.9. The apparatus of claim 8 wherein at least a portion of one of saidmembers is detachably mounted with respect to an immediately adjacentportion for opening said guideway.
 10. The apparatus of claim 7 whereinsaid housing, pinion and part-support insert are formed of a low heatconductive material.
 11. The apparatus of claim 10 wherein said low heatconductive material is phenolic plastic.
 12. Apparatus fortemperature-conditioning elongated molded parts which comprises: a. wallsections defining a horizontally extending chamber; b. a plurality ofheat transfer panels spaced from each other and extending along saidchamber defining generally parallel paths for said parts; c. means forcirculating a heat transfer medium through said panels; d. a pluralityof bar assemblies mounted for movement along the chamber above the heattransfer panels, each bar assembly including annular parts-supportingand rotating meChanisms; e. means for advancing said bar assembliesthrough said chamber; and f. rotating means for turning saidpart-supporting and rotating mechanisms during movement of the barassemblies through the chamber, said rotating means comprising: i. ashaft extending through each bar assembly; ii. worm sections on saidshaft in meshing engagement with the parts-supporting and rotatingmechanisms; and iii. sprockets on the opposite ends of the shaftrotatably engaging the advancing means.
 13. The apparatus of claim 12wherein each bar assembly includes a brake mechanism acting on a portionof the shaft.
 14. The apparatus of claim 12 wherein said advancing meanscomprises dual, endless double stranded chains extending horizontallythrough and situated on opposite sides of said chamber and dual doublesprockets for said chains at opposite ends of the chamber.
 15. Theapparatus of claim 13 wherein said brake mechanism includes a shoe inforced surface contact with said shaft portion and including regulatingmeans for adjustably urging the shoe against the shaft portion. 16.Apparatus for temperature-conditioning elongated molded parts whichcomprises: A. wall sections defining a horizontally extending chamberhaving a feed end and a discharge end, said sections including a floormember dividing said chamber into an upper and a lower course; B. heattransfer assemblies spaced from each other and extending along saidchamber defining generally parallel paths for said parts; C. a pluralityof bar assemblies for supporting said parts in vertical position betweensaid heat transfer assemblies; D. means for advancing said barassemblies through said chamber; and E. metering means for sequentiallyreleasing bar assemblies to the discharge end of the chamber.
 17. Theapparatus of claim 16 wherein said metering means comprises: a. upperand lower metering wheels having radially extending slots therein; b. aboss at opposite ends of each bar assembly for engagement in said slots;and c. drive means for rotating said metering wheels.
 18. The apparatusof claim 16 wherein said means for advancing the bar assembliescomprises: a. endless chains horizontally opposite each other extendingalong said chamber; b. sprockets for said chains mounted for rotarymovement on shafts at the feed and discharge ends of said chamber; andsaid metering means includes: c. a pair of upper metering wheels at thedischarge end of the upper course mounted on one of the shafts of thebar assembly advancing means and spaced from the sprockets thereon, saidwheels having radially extending slots formed therein; d. a pair ofrotatably mounted lower metering wheels at the discharge end of thelower course, said lower metering wheels having radially extending slotsformed therein; e. a boss at each end of each bar assembly forsuccessively engaging the slots in the upper and lower metering wheels;f. a curved, parts-guide member between the upper and lower coursesoutwardly of the sprockets and extending across said chamber; and g.means for rotating said metering wheels in synchronism with each other.19. The apparatus of claim 17 including movable hopper means for theparts beneath the discharge end of the chamber.
 20. The apparatus ofclaim 18 wherein said means for advancing the bar assemblies includes:i. members forming opposing guideways in said wall sections on eitherside of said chamber; ii. rotary followers at opposite ends of eachhousing for bar assembly-supportive movement in said guideways; iii.friction wheels at the end of the upper course at the discharge end ofthe chamber associated with said sprockets for contacting each barassembly as it moves from the upper to the lower course to urge saidfollowers outwardly against surface portions of said guideway-formingmembers.
 21. The apparatus of claim 19 wherein said movable hopper meansand dRive means for rotating the metering wheels are synchronized. 22.Apparatus for temperature-conditioning elongated molded parts whichcomprises: A. wall sections defining a horizontally extending chamberhaving a feed end and a discharge end, said sections including a floormember dividing said chamber into an upper and a lower course; B. heattransfer assemblies spaced from each other and extending along saidchamber defining generally parallel paths for said parts; C. a pluralityof bar assemblies adjacent said heat transfer assemblies for supportingsaid parts in vertical position between said heat transfer assemblies;D. means for advancing said bar assemblies through said chamber; and E.infeed means for sequentially releasing bar assemblies at regularintervals to the upper course of the chamber.
 23. The apparatus of claim22 wherein said infeed means comprises: a. a pair of rotatably mountedescapement wheels at the feed end of the chamber havingcircumferentially spaced, radially extending slots; b. a boss at eachend of each bar assembly for engagement in said slots; and c. powermeans for cyclically rotating said escapement wheels.
 24. The apparatusof claim 22 wherein said means for advancing the bar assembliescomprises: a. endless chains horizontally opposite each other extendingalong said chamber; b. sprockets for said chains on shafts mounted forrotary movement at the feed and discharge ends of said chamber; and saidinfeed means includes: c. a pair of excapement wheels at one end of theupper course at the feed end of the chamber and mounted on the shaft atthe feed end of the means for advancing the bar assemblies, said wheelshaving radially extending slots fored therein; d. a boss at each end ofeach bar assembly for engaging the slots in the escapement wheels; ande. power means for cyclically rotating said escapement wheels.
 25. Theapparatus of claim 24 wherein said power means includes an intermitter.26. Apparatus for temperature-conditioning elongated molded parts whichcomprises: a. wall sections defining a horizontally extending chamber,said chamber having a feed and a discharge end; b. heat transferassemblies spaced from each other and extending along said chamberdefining generally parallel paths for said parts; c. a plurality of barassemblies adjacent said heat transfer assemblies for supporting saidparts in vertical position between said heat transfer assemblies; d.means for advancing said bar assemblies through said chamber; e. gatemeans at the discharge end for releasing the parts from the barassemblies; f. movable hopper means beneath the gate means for acceptingthe released parts; g. metering means for sequentially releasing barassemblies to the discharge end of the chamber; h. auxiliary drive meansfor turning the metering means when the movable hopper means stops; andi. parts collection means beneath the discharge end and adjacent themovable hopper means.
 27. The apparatus of claim 26 including infeedmeans for admitting each bar assembly to the chamber at regularintervals.
 28. The apparatus of claim 26 wherein the metering meanscomprises: i. drive means for turning a pair of metering wheels; andincluding: ii. a clutch assembly in operative cooperation with the drivemeans for the metering wheels and the auxiliary drive means. 29.Apparatus for temperature-conditioning elongated molded parts whichcomprises: A. wall sections defining a horizontally extending chamberhaving a feed end and a discharge end, said sections including a floormember dividing said chamber into an upper and a lower course; B. aplurality of heat transfer panels spaced from each other and extendingalong said chamber defining generally parallel paths for said parts; C.means for circulating a heat transfer medium through said panels; D. aplurality of bar assemblies mounted for movement along the chamber abovethe heat transfer panels, each bar assembly comprising: i. a housinghaving a series of horizontally spaced openings therein in verticalalignment with said paths; ii. an annular pinion seated in each opening;iii. a part-support insert secured to said pinion; E. means foradvancing said bar assemblies through said chamber comprising: i. dualendless double stranded chains extending horizontally through andsituated on opposite sides of said chamber, and ii. dual doublesprockets for said chains at opposite ends of the chamber; F. rotatingmeans for turning each pinion comprising: i. a shaft through each barassembly; ii. worm sections on said shaft in meshing engagement with theannular pinions; and iii. sprockets on opposite ends of each shaft forengaging one of the strands of the double stranded chains; G. membersforming opposing guideways in said wall sections on either side of saidchamber; H. means at opposite ends of each housing for barassembly-supportive movement in said guideways during travel of each barassembly through the chamber; I. metering means for sequentiallyreleasing bar assemblies to the discharge end of the chamber, saidmetering means comprising: i. upper and lower metering wheels havingradially extending slots therein; ii. a boss at each end of the shaft ofeach bar assembly for engagement in said slots; and iii. drive means forrotating said metering wheels; J. movable hopper means for the partsbeneath the discharge end of the chamber; K. gate means between thelower metering wheel and the movable hopper means for releasing theparts from the bar assemblies; L. infeed means for releasing each barassembly at regular intervals to the upper course of the chamber, saidinfeed means comprising: i. a pair of rotatably mounted escapementwheels at the feed end of the chamber having circumferentially spaced,forwardly directed, radially extending slots for said bosses; and ii.power means for cyclically rotating said escapement wheels; M. auxiliarydrive means for turning the metering wheels when the movable hoppermeans stops; and N. parts collection means beneath the discharge endadjacent the movable hopper means.